Cylinder construction for internal combustion engines



April 23, 1963 c. M. BOVARD CYLINDER CONSTRUCTION FOR INTERNAL COMBUSTION ENGINES 3 Sheets-Sheet 1 Filed Nov. 14. 1960 INVENTOR: E. M. B 0101122.

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April 23, 1963 c. M. BOVARD CYLINDER CONSTRUCTION FOR INTERNAL COMBUSTION ENGINES Filed Nov-.. 14. 1960 3 Sheets-Sheet 2 FIG-3- ATTYE.

April 23, 1963 c. M. BOVARD CYLINDER CONSTRUCTION FOR INTERNAL COMBUSTION ENGINES 3 Sheets-Sheet 3 Filed Nov. 14. 1960 INVENTOR. L7. M.B D'YAHD.

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United States Patent CYLINDER CONSTRUCTION FOR INTERNAL COMBUSTION ENGINES Charles M. Bovard, Mount Vernon, Ohio, assignor to The Cooper-Bessemer Corporation, Mount Vernon, Ohio, a corporation of Ohio Filed Nov. 14, 1960, Ser. No. 68,880

2 Claims. (Cl. 12341.8)

This invention relates to internal combustion engines and is particularly directed to a cylinder construction for a high output compression ignition engine.

The primary object of the invention is to provide a unit cylinder construction for high output compression ignition engines in which the cooling properties are improved and in which a stronger, more durable cylinder head is provided, both contributing to a marked increase in the power capability of the cylinder unit.

Another object of the invention is to provide a unit cylinder construction in which a head liner portion of the engine cylinder is replaceable as a unit, being installed from the bottom of the cylinder shell.

Another object of the invention is to provide high velocity direct water cooling passages for both the cylinder liner and cylinder head insert or liner whereby improved cooling of the cylinder liner and head is established.

Other objects and advantages of the invention will become apparent from the following detailed description of a preferred embodiment thereof, reference being had to the accompanying drawings, in which:

FIG. 1 is an end elevational view, with parts broken away and parts in section of a high output compression ignition engine constructed in accordance with the present invention;

(FIG. 2 is a central vertical sectional view of a unit cylinder embodying the present invention;

FIG. 3 is a side elevational view of a cylinder liner;

FIG. 4 is a top plan view of the cylinder liner shown in FIG. 3;

'FIG. 5 is a side elevational view, with parts broken away, of a cast steel head insert forming a part of the present invention;

FIG. 6 is a sectional view on line 6-6 of FIG. 2;

FIG. 7 is a somewhat enlarged fragmentary sectional view of a portion of the unit cylinder showing in detail the water passages through the cylinder head portion;

FIG. 8 is a section on line 8-8 of FIG. 2 or FIG. 5 on a somewhat enlarged scale;

fuel pumps are mounted. Engines of this type having separate power elements have been known in the art. A

7 power element includes a power cylinder 22 of the wet liner type, the liner being designated 24 and being shown in side elevation in FIG. 3. A crankshaft 26 is journaled in the engine base and, in the case of a V-type engine as shown in the drawings, is connected to articulated connecting rods 28 on which pistons '30 are mounted. Suitable air intake manifolds 32 and exhaust manifolds 34 are connected to the power elements.

Each power element includes a fuel pump 36- by which fuel is supplied to an injector nozzle 38, the pumps being operated by a common fuel pump cam shaft 40 mounted in the engine base and driven by and in timed relation to used.

the crankshaft 26 by a drive train that is conventional and not shown.

Further, each power element includes suitable valve gear operated by a cam shaft 42 in a conventional manner. The valve gear may take any suitable form, dual intake valves 44 and dual exhaust valves 46 being shown. The four valves for each power element are operated by conventional pushrods and rocker arms from the cam shaft 42.

'Referring particularly to FIG. 2, a unit cylinder embodying the present invention is there shown in section and apart from .the conventional apparatus with which it is T he cylinder includes an outer casting 50, usually of cast iron, that is cored to form passages for intake and exhaust gases, cooling water, etc. The casting is substantially closed across the top so that the cylinder head portion and liner are inserted through the open bottom of the casting. Unit cylinders of this general type are known and have been used successfully in the past for engines of limited output. In these prior engines, however, the cylinder head has been made integral with the outer casting 50 and thus of the same cast iron. As the output of the engines has increased, it has been found that known unit cylinder designs operate at such high temperatures and develop such high internal thermal stresses that failures are apt to occur unless the engine is restricted to operation at outputs below those which are desirable, and of which the remainder of the engine is fully capable. With conventional cast iron cylinder heads, for example, the thermal stresses occurring at high output are frequently sufficient to crack the heads in the area of the injection nozzle which is in the center of the head in a most difiicult position from a cooling standpoint.

, now known.

In accordance with the present invention the head portion of the cylinder comprises an insert designated generally 52 and including an inner steel casting 54 in which air intake .channels 55 and exhaust passages 56 are formed, together with a central boss forming a recess 57 for the reception of the injection nozzle 38. The inner casting 54 thus comprises a top wall, a bottom wall, and connecting walls comprising the gas passages 55 and 56 and injector receiving boss '57. The insert 52 is completed to its hollow form by placing a ring 60 of the same steel material around the casting and welding it to the top and bottom walls as at 62, 63. The ring is, of course, cut out at the areas overlying the entrance to the intake and exhaust passages 55 and 56.

By making the cylinder head insert of cast steel, the valve seats can be facedv with a hard metal alloy such as Stellite by welding the hard rnetal directly to the steel and grinding to shape. This direct application is not possible with the usual gray iron cylinder head because a weld lower wall of the head must be made thick enough to accept the insert. Thus the steel head insert of the present invention can be made with a thinner lower wall and more readily cooled because of its better heat transfer, and less subject to warping because the heat stresses set up therein are lower.

In some instances, particularly on relatively large engines, the flow of cooling water is greatly improved by the use of baffles 64 which are welded to the casting 54 at a predetermined height above the lower wall thereof, the weld being conveniently made either to the sides of the walls of the intake and exhaust gas passages or to the interior wall of the ring 60 prior to assembly. These baffles serve to keep the entering cooling Water against the lower wall of the casting for a longer period and to direct this water inwardly toward the injector receiving boss 57. The flow path of the cooling water will be subsequently described in detail. The assembled baffles 64 and the resulting water passages are best shown in FIGS. 2 and 8.

The main cylinder unit casting 50 includes a water supply passage 66 having an opening 67 leading to the space around the liner 24, and the outer surface of the liner is provided with a series of helical lands 68 which cooperate with the adjacent surface of the casting 50 to form a plurality of upwardly directed helical water passages 69. The lands 68 begin at a line opposite the lowest point of travel of the piston in the liner since this represents about the lower margin of the area of greatest heat in the cylinder. Below this the liner remains relatively cool and the directed flow accomplished by the passages 69 is not required. The liner 24 is provided with an attaching flange 70 near its lower end and is bolted or otherwise fixed to the cylinder casting 50 by bolts passing through this flange. A suitable water seal 71 is provided to prevent leakage of cooling Water past the lower end of the liner.

In those instances in the prior art with which I am familiar where directing water passages are formed around the cylinder liner, the walls of the passages have been formed primarily in the cylinder block and the exterior of the liner has been in the form of a smooth cylinder. In the present instance, by contrast, the helical passages 69 are formed primarily by convolutions in the exterior wall of the liner. This leads toimproved heat transfer to the cooling water because the heat flows from the cylinder into a continuous metal body surrounded on three sides by the coolant. In the prior art there is a discontinuity at the hottest point, adjacent the exterior Wall of the smooth liner which impedes the heat transfer. The present invention increases by four or five times the area of the liner surface exposed to coolant.

Each of the helical water passages 69 terminates at its upper end in a common peripheral passage 72 (see FIGS. 2 and 3). The lower wall of the head casting 54 is drilled with a series of inwardly directed cooling water openings 73 serving as transfer passages between the common periperal passage 72 and the interior of the hollow insert 52. Thus, cooling water entering the space around the liner from supply opening 67 is forced through the helical passages 69 and the openings 73 into the cylinder head insert, and enters the insert below the baifle 64. The water or other coolant then passes across the lower wall of the cylinder head insert which is exposed to combustion gases and, of course, around the lower end of the exhaust passages 56. Since these parts operate at the highest temperatures, adequate cooling is assured because the coolant is forced to flow over the surfaces before passing to the remaining upper parts of the head insert.

In any engine cylinder of this type the hottest area is at the upper end of the cylinder liner. In most instances the liner is provided with a peripheral attaching or seating flange of considerable thickness at this point. This large body of metal is difficult to cool and is usually a limiting factor in performance. In the case of the present invention the upper edge of the liner can be made very thin and is cooled by water inthe peripheral passage 72 much more eflectively than in those cases where there is a flange at this point and no transfer of coolant from the block to the head.

A suitable water discharge conduit is provided in the form of a tubular jumper member 75 best shown in FIGS. 7 and 10. At its lower end the tubular member is provided with spaced peripheral sealing elements such as O-rings 76 seated in grooves 77. One of the rings seals against an adjacent surface of the insert, while the other seals against an adjacent surface of the outer main unit casting 50 which is provided with a cooling water discharge passage 78. The jumper is held in its assembled position by a cap member 79 bolted to the casting 50 by bolts 80.

The cylinder head insert 52 is held in place in the unit cylinder casting 50 not only by upward pressure from the cylinder liner, but additionally by bolts 82 which extend through an inturned flange 84 of the outer casting 50.

The upper and lower edges of the insert 52 are sealed against gas and water leakage by gaskets 85 and 86, while Water leakage between the cylinder liner 24 and the lower surface of the head insert 52 is prevented by a gasket 87. Sealing at the junction between the head insert and cylinder liner is facilitated by machining complemental stepped surfaces on the parts.

As previously noted, the cast steel material of the head insert 52 is much more ductile than cast iron and is capable of withstanding much greater thermal stress than cast iron without cracking. Further, the fact that the insert 52 is made as a separate element capable of expanding separately from the cast iron cylinder unit 50 also contributes to the ability of the engine to be run at much higher outputs than similar engines in which an integral cast iron head is employed. The heat distribution in the cast steel insert is, of course, largely dependent on the flow characteristics of the cooling water.

The flow of liquid coolant through the engine commences with the entrance of Water or other coolant under pressure in the supply passage 66 to the space around the liner 24. The liquid then passes upwardly around the liner in the helical paths 69 determined by lands 68. The separate streams are united in the common peripheral passage 72 at the top of the liner and from this passage the coolant enters the series of openings 73 to pass into the head insert 52. Instead of merely flowing into and through the cylinder head in accordance with normal practice, the coolant in the present instance is held against the lower hot surface of the casting by batfles 64 so that its flow across this surface is substantially prolonged and the efliciency of the heat exchange is greatly im proved. After passing the inner edges of the baffles 64 the coolant passes into the volume above the baffles and out through the jumper 75.

Since the heat exchange between the coolant and the lower surface of the insert is greatly improved and is controllable, and because of the toughness of the steel material from which the insert is cast, the engine according to the present invention is capable of burning larger quantities of fuel per stroke and thus of higher output. Inserting the head casting through the lower end of the unit cylinder 50 is advantageous over simply bolting a cylinder head in place on a cylinder.

While the invention has been disclosed in conjunction with a specific form and disposition of the parts, it should be expressly understood that it is capable of numerous modifications and changes without departing from the spirit and scope of the appended claims.

What I claim is:

1. A unit cylinder for an internal combustion engine comprising an outer body having a substantially closed upper end and having means to enable attachment to an engine frame, a cylinder liner received through the lower end of said outer body, a cylinder head insert also received through the lower end of said body ahead of said cylinder liner, said insert and said liner having complemental sealing surfaces at their meeting areas, means on said liner forming a plurality of helical coolant passages terminating in a common chamber at the combustion end of said liner, said insert having a plurality of coolant openings from said common chamber whereby said insert receives coolant, means within said insert to direct coolant across that face of said insert which is exposed to combustion gases, means to introduce coolant at the lower end of said helical passages, and a jumper means to discharge coolant from Within said insert.

2. A unit cylinder for an internal combustion engine comprising an outer body having a substantially closed upper end and having means to enable attachment to an engine frame, a cylinder liner received through the lower end :of said outer body, a cylinder head insert also re ceived through the lower end of said body ahead of said cylinder liner, said insert and said liner having complemental sealing surfaces at their meeting areas, said insert being free to expand and contract independently of said outer body, means to introduce coolant around said liner and into said insert, and means within said insert to direct the flow of coolant across that face of said insert which is exposed to combustion gases.

References Cited in the file of this patent UNITED STATES PATENTS Regenbogen et a1. Oct. 12, Sims Dec. 3, Willgoos Sept. 12, Tacchella J an. 4, Ricardo Mar. 15, Hollis Apr. 21,

FOREIGN PATENTS Great Britain Jan. 19, 

1. A UNIT CYLINDER FOR AN INTERNAL COMBUSTION ENGINE COMPRISING AN OUTER BODY HAVING A SUBSTANTIALLY CLOSED UPPER END AND HAVING MEANS TO ENABLE ATTACHMENT TO AN ENGINE FRAME, A CYLINDER LINER RECEIVED THROUGH THE LOWER END OF SAID OUTER BODY, A CYLINDER HEAD INSERT ALSO RECEIVED THROUGH THE LOWER END OF SAID BODY AHEAD OF SAID CYLINDER LINER, SAID INSERT AND SAID LINER HAVING COMPLEMENTAL SEALING SURFACES AT THEIR MEETING AREAS, MEANS ON SAID LINER FORMING A PLURALITY OF HELICAL COOLANT PASSAGES TERMINATING IN A COMMON CHAMBER AT THE COMBUSTION END OF SAID LINER, SAID INSERT HAVING A PLURALITY OF COOLANT OPENINGS FROM SAID COMMON CHAMBER WHEREBY SAID INSERT RECEIVES COOLANT, MEANS WITHIN SAID INSERT TO DIRECT COOLANT ACROSS THAT FACE OF SAID INSERT WHICH IS EXPOSED TO COMBUSTION GASES, MEANS TO INTRODUCE COOLANT AT THE LOWER END OF SAID HELICAL PASSAGES, AND A JUMPER MEANS TO DISCHARGE COOLANT FROM WITHIN SAID INSERT. 